The field of this invention relates to a gate operating mechanism and more particularly to a mechanism for operating a horizontally sliding gate which is designed to traverse a substantial distance such as between ten and twenty feet. The gate generally is to be located in an outdoors environment and normally has a substantial weight of between three hundred and one thousand pounds.
It is common for electrical motor driven gates to employ a control mechanism that is to either stop the gate or stop and reverse the gate if the gate incurs an unexpected amount of resistance during opening or closing. Outside gates are commonly constructed of a weather resistance material such as wrought iron. It is common for such gates to traverse a roadway of twenty feet or more in width. A gate constructed of wrought iron that is designed to traverse that width inherently has substantial weight. It is common for such gates to weigh as much as one thousand pounds. Operation of the gate can be by any of various input devices such as a hand-held transmitter, sensor loops buried in the roadway, photoelectric eyes, or push buttons mounted some distance from the gate. Convenient gate operation is accomplished by any of the above where it is desired to do so automatically.
Designed within the electronic circuitry of such gates it is common to include safety devices. It is the intent and purpose of these safety devices that if the gate incurs some kind of an obstacle that the gate will either stop or stop and reverse. A typical obstacle would be contacting a motor vehicle or contacting a human being. However, these gates are of a substantial weight and if, for example, you have a thousand pound gate contacting a child, the safety device is commonly just not sensitive enough to cause the gate to stop or stop and reverse without causing injury to the child. If the gate contacts an automobile, there can be some damage to the automobile before the gate will reverse. In actual practice, there are recent incidents, though few, where children have been killed with automatic gates. Also, there are recent instances where even adults have incurred arm and leg damage from such gates. Fortunately, these instances are isolated but they do occur. There are also many occurrences of damage such as motor vehicle damage caused by such automatic gates.